Mundelein, IL has a population of 31,550 and is the 1,354th largest city in the United States. The population density is 3,308 per sq mi which is 1388% higher than the Illinois average and 3551% higher than the national average. The median age in Mundelein is 37 which is approximately 1% lower than the Illinois average of 37. In Mundelein, 63% of the population over 15 years of age are married, 62% speak English and 24% speak Spanish. 55% of Mundelein residents were born in Illinois, 17% were born out of state, 1% were born outside of the United States and 27% were foreign born.